The study, authored by Yixian Sun and Yitong Ye of the University of Bath, examines how Trump’s second-term anti-climate agenda is reconfiguring global climate governance and how different actors around the world are responding. Their central claim is that the architecture of global climate action has become polycentric, meaning that authority is distributed across many overlapping centers, including national governments, subnational states, cities, businesses, and transnational networks. Because no single actor, not even the world’s largest economy, dominates the system, the withdrawal of one major player cannot collapse the whole regime. The researchers compare this to a safety net: when one strand fails, the others hold the structure together.

The scale of the American retreat is nonetheless unprecedented. Unlike the first Trump administration, whose rollbacks were largely regulatory and reversible, the 2025 agenda targets structural foundations. Beyond the Paris exit, the administration suspended disbursement of tax credits and funds authorized under the Inflation Reduction Act, the largest public investment program in US history, which had mobilized roughly 370 billion dollars for renewable and zero-emission technologies. Federal policy has been reoriented toward expanding domestic oil, gas, and coal production under banners of energy dominance and economic security, deepening what the authors call the structural lock-in of a high-carbon economy.

The rollback has even extended to pressuring private climate action. In August 2025, 23 Republican state attorneys general sent a letter to the Science Based Targets initiative, a global standard-setter for corporate net zero commitments, demanding disclosures about its governance and membership on antitrust and consumer protection grounds. The researchers note that such threats from subnational governments to non-state climate initiatives are unprecedented and could deter US-based companies from pursuing decarbonization. Meanwhile, a 90-day freeze on foreign assistance and the closure of USAID terminated more than 150 climate-related contracts and grants worth roughly 1.2 billion dollars, while the administration rescinded 4 billion dollars previously pledged to the Green Climate Fund and withdrew from the Loss and Damage Fund.

These cuts strike hardest at developing countries, which have long relied on American finance to access clean technologies, build institutional capacity, and manage climate-induced losses. The authors frame this as a philosophical shift in US foreign policy, away from cooperative leadership based on providing global public goods and toward coercive influence exercised through punitive measures such as tariffs. In the Trumpist worldview, international commitments are constraints on American sovereignty, and climate finance is a zero-sum transaction that benefits other countries at America’s expense. The resulting trade tensions, particularly with China, the principal supplier of clean technologies, have raised costs for solar panels, batteries, and electric vehicles in the US market.

Yet the multilateral system has refused to buckle. No other member state has followed the United States out of the Paris Agreement. Instead, most countries have continued updating their Nationally Determined Contributions, the five-yearly pledges that form the treaty’s ratcheting mechanism. By early November 2025, 108 parties excluding the US had officially submitted their 2035 targets, together accounting for 65.3 percent of global emissions and 55.3 percent of the world’s population. In July 2025, China and the European Union jointly committed to submit enhanced 2035 pledges before the COP30 summit and to demonstrate shared leadership in advancing net zero transitions.

China’s announcement on 24 September 2025 was particularly consequential. President Xi Jinping pledged emission reductions of 7 to 10 percent below peak levels by 2035, an increase in non-fossil fuels to more than 30 percent of energy consumption, and an expansion of wind and solar capacity to over six times 2020 levels. Although analysts debate the ambition of these targets, it marks the first time China has promised an absolute cap on its greenhouse gas emissions, and the country may overperform given its current pace of clean energy deployment. Brazil, meanwhile, has pledged to cut emissions 59 to 67 percent below 2005 levels by 2035 and intends to use its COP30 presidency to keep global ambition aligned with the Paris goals.

Within the United States itself, subnational and non-state actors are sustaining momentum. Twenty-four states and territories have formed the US Climate Alliance, representing nearly 60 percent of the national economy, and have collectively reaffirmed a net zero target of reducing emissions 50 to 52 percent below 2005 levels by 2030. States such as California, Washington, and Massachusetts continue to operate renewable portfolio standards, cap-and-trade systems, and electric vehicle mandates. Even Republican-leaning Texas, the largest oil and gas producing state, has become a renewable powerhouse, holding more than 26 percent of US wind capacity in 2022 and attracting over 21 billion dollars in solar investment by early 2023. City networks like C40, which includes 14 major American cities, have pledged to remain bastions of climate progress, and the share of large US companies adopting net zero targets has continued to rise even during Trump’s second term.

Perhaps the most striking evidence of resilience comes from the Global South, where cheap solar technology is driving a consumer-led energy revolution. In Nigeria, savings from reduced diesel imports allow solar panels to pay for themselves within six months. In Sierra Leone, imported panels could generate electricity equivalent to 61 percent of the country’s 2023 output if fully installed. Pakistan recorded one of the fastest solar expansions in history by importing 16 gigawatts of panels during 2024 alone. With American climate finance gone, new funding sources are filling the gap, most notably China, which provided an estimated 3 billion dollars annually for developing country climate action between 2015 and 2021 and has pledged overseas green investments of up to 71.6 billion dollars, particularly through the Belt and Road Initiative since 2022.

The Bath researchers conclude that Trumpism has limited purchase on a polycentric system in which many actors have strong, increasingly economic incentives to decarbonize. Climate politics, they argue, is no longer primarily a collective action problem but a distributional one, with countries and firms competing for the benefits of clean energy markets. As climate impacts intensify and green technology costs fall, the actors positioned to gain from transition are strengthening their commitments rather than abandoning them. The long-term consequences of America’s retreat remain uncertain, and the damage to US decarbonization and to vulnerable countries is real. But the evidence assembled suggests that the global net zero machine, powered by major emitters, American states and cities, corporations, and Chinese capital, will keep turning regardless of what happens in Washington.

Subject of Research: The resilience of polycentric global climate governance under the second Trump administration's climate policy rollback

Article Title: Global climate governance remains resilient under Trump 2.0

Article References: Sun, Y., & Ye, Y. (2025). Global climate governance remains resilient under Trump 2.0. Global Public Policy and Governance, 5(4), 353-366. https://doi.org/10.1007/s43508-025-00131-x

Image Credits: AI Generated

DOI: 10.1007/s43508-025-00131-x

Keywords: climate governance, Paris Agreement, Trump administration, net zero, polycentricity, climate finance, China, Nationally Determined Contributions, US Climate Alliance, renewable energy, Global South, COP30

The central premise of the study is deceptively simple but consequential: cities do not function as islands. Labor markets, innovation networks, infrastructure systems, and digital services routinely spill over municipal borders, tying together core cities, suburbs, and smaller towns into integrated functional regions. If smart city performance—measured through indicators of digital infrastructure, technological innovation, human capital, and connected urban services—is produced within these wider regional systems, then assessments that stop at the city limit risk misreading both the sources and the consequences of urban smartness. The authors argue that regional scaling, the way performance changes with the size of a regional system, provides a crucial test of whether smart urban capabilities are driven by local assets or by broader structural dynamics.

To carry out this analysis, the research assembles regional-level data across European territories, combining indicators of smart urban development with measures of regional population, economic output, and spatial structure. The methodological logic draws on scaling analysis, an approach borrowed from complexity science that has previously been used to show how many socioeconomic outputs—from patents to wages to the incidence of certain social phenomena—tend to increase superlinearly with city size. Applied at the regional scale, the question becomes whether smart performance grows proportionally, sublinearly, or superlinearly as regions become larger and more densely connected, and whether that scaling behavior differs systematically across parts of Europe.

The study’s mapping of spatial distribution reveals a sharply uneven geography. Smart urban capabilities cluster in a limited set of regions, typically those anchored by large metropolitan areas with strong research institutions, dense producer-service sectors, and well-developed digital infrastructure. This pattern echoes long-standing observations about European spatial economics, including the persistence of a core-periphery gradient running roughly from the so-called blue banana of urbanization through southern Germany, the Low Countries, and parts of northern France, toward more sparsely provisioned peripheral regions in southern and eastern Europe. But the regional analysis adds an important nuance: proximity to a high-performing core does not automatically translate into high regional performance, and some regions without globally famous capitals nonetheless demonstrate robust smart urban profiles built on secondary cities and coordinated regional networks.

The scaling results carry particular significance for urban policy. When the researchers examine how smart performance varies with regional size, they find evidence that the relationship is not uniform across Europe. In some regional contexts, performance rises more than proportionally with size, consistent with agglomeration effects in which larger, denser regional systems generate disproportionate returns on digital and innovative activity. In others, the relationship flattens or weakens, suggesting diminishing returns or structural constraints—such as fragmented governance, uneven infrastructure investment, or dependency on a single urban core—that prevent large regions from converting size into smart performance. This heterogeneity undermines the idea that there is a single universal law of smart urban growth and instead points to regionally specific development regimes.

One of the study’s most provocative implications concerns the proliferation of smart city rankings and benchmarks. Municipal league tables, the authors suggest, can be misleading in two directions. A small city may appear exceptionally smart on a per-capita basis while depending heavily on regional universities, transport systems, and firms headquartered elsewhere; conversely, a sprawling polycentric region may look mediocre when judged by its largest municipality alone while its distributed network of towns collectively delivers strong digital and innovative capacity. By evaluating performance at the regional scale, the study provides a corrective that better reflects how the production of smart urban outcomes is actually organized in functional space.

The findings also speak to a central debate in regional science: the tension between concentration and dispersion of high-value activities. If smart capabilities reward agglomeration with superlinear returns, then market forces and even some policy interventions will tend to deepen regional inequality, funneling talent, investment, and infrastructure toward already advantaged metropolitan areas. The study’s evidence of heterogeneous scaling offers a more hopeful reading. Where regional systems—particularly polycentric ones with multiple cooperating cities—achieve strong performance, the lesson is that scale advantages are not the exclusive property of single dominant metropolises. Connectivity, complementarity, and coordinated governance among smaller cities can substitute, at least in part, for raw metropolitan size.

For European policymakers, the research lands at a moment when cohesion policy, digital transition funding, and smart city programs are being recalibrated. The European Union’s digital and green transitions explicitly target territorial balance, yet the study suggests that policy instruments designed around individual municipalities may systematically miss the regional systems in which smart performance is actually produced. Investment in broadband or innovation vouchers allocated city by city may underperform relative to instruments that reward inter-municipal cooperation, shared regional data platforms, and integrated transport-and-digital planning. The scaling evidence implies that the effectiveness of such interventions will differ by regional context, arguing for territorially differentiated strategies rather than one-size-fits-all smart city templates.

The study is candid about the limits of its evidence base. Regional indicators of smart urban performance remain imperfect proxies for the underlying phenomena they seek to capture, and data availability varies across countries, complicating pan-European comparison. Scaling relationships, moreover, are correlational: demonstrating that performance rises with regional size does not by itself identify the mechanisms—labor pooling, knowledge spillovers, infrastructure economies, or network effects—that drive the pattern. The authors call for finer-grained, longitudinal work that can trace how regional smart performance evolves over time and how specific policies alter scaling behavior. Still, the analysis marks a meaningful step in relocating the smart city debate from the showcase municipality to the regional systems in which urban intelligence is embedded.

In the end, the research reframes a familiar question with fresh analytical force. The smart city narrative promised that technology would make urban life more efficient, sustainable, and responsive; this study suggests that whether that promise is fulfilled depends less on any single city’s gadgetry than on the scale, structure, and connectivity of the regions those cities inhabit. As Europe confronts the twin challenges of digital transformation and territorial cohesion, the message is clear: the future of smart urbanism will be decided not city by city, but region by region, and policies that recognize this spatial reality are far more likely to deliver smartness that is both high-performing and broadly shared.

Subject of Research: Spatial distribution and regional scaling of smart city performance across European regions

Article Title: Beyond smart cities: spatial distribution and regional scaling performance in European regions

Article References: Dai, Y., Hasanefendic, S., & Bossink, B. (2026). Beyond smart cities: spatial distribution and regional scaling performance in European regions. npj Urban Sustainability. https://doi.org/10.1038/s42949-026-00474-2

Image Credits: AI Generated

DOI: 10.1038/s42949-026-00474-2

Keywords: smart cities, European regions, urban scaling, regional development, urban sustainability, digital infrastructure, spatial distribution, agglomeration, territorial cohesion, polycentricity, regional policy, complexity science